Athletic turned down a first offer from the Turin powerhouse earlier in January, but they have now made a final offer worth €4m, plus a €300,000 bonus if Juventus successfully defend their Serie A title.

A winter transfer remains a complicated matter as Llorente's current employers are determined to hold on to the player until his contract runs out.

The Primera Division side do not need the funds a transfer would generate, having sold Javi Martinez to Bayern Munich for €40m in the summer transfer window, and they see keeping the 27-year-old Llorente at the club as a matter of pride.

Should Athletic turn down Juventus' ultimatum, the Bianconeri will look to immediately purchase the other half of Ciro Immobile's contract from Genoa, while they could leave the Italy Under-21 star at his co-owned club until the end of the season if Llorente arrives this month.

Juventus held talks with Genoa over Immobile on Tuesday, but the Grifone have told the Serie A leaders that they want to sign a replacement for the striker first before letting go of the player.